亚急性轻度缺氧增加组胺刺激的肺动脉内皮细胞钙振荡频率

摘要

钙振荡(calciumoscillation)能以频率解码的形式调节基因转录,钙振荡的频率可反应基因转录的水平.为探索持续缺氧是强化还是钝化肺动脉内皮细胞对组胺的反应,研究了24 h亚急性轻度缺氧对组胺刺激的肺动脉内皮细胞钙振荡频率的影响,并探索了其机制.结果是:a.24 h亚急性轻度缺氧可显著增加组胺刺激的肺动脉内皮细胞钙振荡频率;b.NADPH氧化酶抑制剂,diphenylene iodonium chloride(DPI,10 μmol/L)消除了组胺刺激的常氧和缺氧后肺动脉内皮细胞钙振荡;c.黄嘌呤氧化酶抑制剂,别嘌呤醇(oxypurinol,100 μmol/L)能显著降低组胺刺激的缺氧后肺动脉内皮细胞升高的钙振荡频率,但降低后的钙振荡频率仍高于常氧组,别嘌呤醇对组胺刺激的常氧组肺动脉内皮细胞钙振荡频率无显著影响.以上结果表明,在持续缺氧相关的肺疾患中,肺动脉内皮细胞对组胺反应的敏感性增加.NADPH氧化酶在组胺刺激的钙振荡的发生中发挥重要作用;黄嘌呤氧化酶的激活是缺氧引起组胺刺激的钙振荡频率增加的重要原因.%Calcium oscillation may regulate gene transcription in a frequency-decoding manner during agonist stimulation,which provides an indicator of transcription level in cells. To determine whether persistent exposure to hypoxia may sensitize or blunt cell response to histamine, the effects of 24 h subacute mild hypoxia on histamine-stimulated calcium oscillation frequency were examined in pulmonary artery endothelial cells (PAECs). The results are: (1) 24 h subacute mild hypoxia significantly increased the histamine-stimulated calcium oscillation frequency in PAECs. The averaged frequency of calcium oscillation in posthypoxic PAECs was significantly higher than that in normoxic ones. (2) NADPH oxidase inhibitor, diphenylene iodonium chloride (DPI, 10 μmol/L), abolished histamine-stimulated calcium oscillations both in normoxic and posthypoxic PAECs. (3) Xanthine oxidase inhibitor, oxypurinol (100 μmol/L), did not affect the calcium oscillation kequency in normoxic PAECs. However, it significantly decreased the elevation of calcium oscillation frequency in posthypoxic PAECs. These results demonstrated that, during pulmonary disease related to persistent hypoxia,PAECs become more sensitive to histamine. During histamine stimulation, NADPH oxidase plays a critical role in generating calcium oscillations, while xanthine oxidase may contribute to, at least in part, the increase of calcium oscillation frequency in posthypoxic PAECs.